The long-term objectives of this proposed project are to develop a noninvasive method for quantitative assessment of the extent of intestinal mucosal surface area involved in celiac disease. The proposed approach is based on the hypothesis that under certain experimental conditions changes in mucosal surface area are quantitatively reflected in the absorption of a dose of 13C-labeled saturated long-chain fatty acid. Thus, we propose to develop a method for accurate and noninvasive measurement of absorption of a dose of 13C-palmitic acid ingested under standard test conditions by the celiac patients. The method is based on measurement of the ratio of 13C-Excess/Dy in a sample of feces from the patient after ingestion of a standard dose of 13C-palmitic acid and DyCl3. During Phase-I of this project, we will show the validity of our approach by making appropriate measurements in ten children with firm celiac diagnosis before and after institution of a gluten free diet (GFD) which is the standard therapy for this disease. During Phase-II of the project, we will show the expected linear correlation between the extent of intestinal mucosal involvement and absorption of the labeled-fatty acid. The outcome of this research will be availability of a "Test Kit" for this purpose, which will be marketed both for routine clinical applications and for research purposes. PROPOSED COMMERCIAL APPLICATIONS: This project will lead to availability of a new noninvasive tool to evaluate mucosal surface area for management of celiac patients.